From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: Type invariants and private extensions?
Date: Tue, 12 Sep 2017 09:30:13 +0200
Date: 2017-09-12T09:30:13+02:00 [thread overview]
Message-ID: <op82e5$kq5$1@gioia.aioe.org> (raw)
In-Reply-To: op7125$1186$1@gioia.aioe.org
On 12/09/2017 00:00, Victor Porton wrote:
> It seems that you don't understand me: I need different boolean functions
> for different derived tagged types.
Well, but that is not invariant, at least not formally. The invariant of
the parent type must hold on the derived type, otherwise the instances
of the latter would not be substitutable for the former.
In effect this means that you can only strengthen the invariant by
adding new conjunction elements, if you inherit any in-operation or use
it in any class-wide in-operations, i.e. basically anywhere.
--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
next prev parent reply other threads:[~2017-09-12 7:30 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-11 19:51 Type invariants and private extensions? Victor Porton
2017-09-11 20:00 ` Egil H H
2017-09-11 20:48 ` Victor Porton
2017-09-11 21:19 ` Egil H H
2017-09-11 21:27 ` Victor Porton
2017-09-11 21:49 ` Egil H H
2017-09-11 22:00 ` Victor Porton
2017-09-11 22:06 ` Egil H H
2017-09-12 7:30 ` Dmitry A. Kazakov [this message]
2017-09-11 22:00 ` Jere
2017-09-11 22:02 ` Victor Porton
2017-09-12 18:26 ` Jeffrey R. Carter
2017-09-12 18:54 ` Victor Porton
2017-09-12 19:56 ` Jeffrey R. Carter
2017-09-12 20:08 ` Victor Porton
2017-09-12 22:34 ` Shark8
2017-09-12 22:59 ` Victor Porton
2017-09-13 4:21 ` Jere
2017-09-13 4:28 ` Jere
2017-09-13 4:34 ` Jere
2017-09-14 13:52 ` Victor Porton
2017-09-15 0:48 ` Jere
2017-09-16 14:22 ` Victor Porton
2017-09-14 7:28 ` Shark8
2017-09-14 13:56 ` Victor Porton
2017-09-14 13:58 ` Victor Porton
2017-09-11 22:48 ` Shark8
2017-10-02 23:16 ` Randy Brukardt
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